The upcoming typesystem for Elixir will be a gradual type system, so you will not be required to write any types even after it lands (and you will still benefit from the typechecker either way).
Author here... I wasn't the one who posted this article to HN and upvoted it. Hell, I don't even have analytics on my website, so I had no idea. You can't really blame me for sharing my thoughts.
But yeah, static typing in some circles is a racket. Typescript has been a royal pain in the ass because people think a type system solves everything, but it can't solve side-effects no matter how well-typed they are.
Tests are always going to be my safety harness, not a promise from the compiler that my shit is sound.
The author's joy will also be short-lived because static typing is coming and will likely win out if the implementation is solid.